Concrete joint



w. F. MIDDLESTADT 3,038,395

' INVENTOR /LL/fiM E June 12, 1962 United States Patent 3,038,395 CONCRETE J OKNT William F. Middlestadt, 4040 The Alameda, Baltimore 18, Md. Filed June 9, i958, Ser. No. 740,858 8 Ciaims. (ill. 94-18) This invention relates to a method for forming a concrete joint and to a tubular element which is adapted to form a joint in concrete pavement and the like. The present application is a continuation-in-part of application Serial No. 727,160 filed April 8, 1958, now abandoned.

Heretofore two methods have been principally used in forming joints. According to one prior art method the joints are preformed by using a filler strip of cardboard or the like and this filler strip is inserted into the concrete after the pavement has been poured. After the concrete is cured the filler strip is removed and the joint filled with sealing compound. This method has not proved to be entirely satisfactory in that it is difficult to remove the filler piece after the concrete has cured and furthermore the filler piece cannot be of sufiicient strength to maintain a smooth joint as it absorbs moisture and tends to lose its shape. After the filler piece is removed but prior to filling the joint with a sealing compound foreign matter can enter the joint and this foreign matter is subsequently sealed into the joint by the sealing compound. As the concrete contracts, producing a crack in the concrete beneath the formed recess, the sealing compound tends to migrate towards the subgrade and thus producing a void space and uneven surface at the joint.

Another prior art method involves actually cutting the joint by a saw while the concrete is in a partially hardened condition but prior to the time that it is completely cured. Such a method produces an even Well-formed joint but saw blade costs can be exceedingly high depending upon the character of the aggregates used in the concrete. Furthermore, this method requires the pavement to be disturbed prior to complete curing and this, of course, is highly undesirable.

In both of the prior are methods described above difficulty is encountered in connection with maintaining the surface of the joint level with the pavement during expansion and contraction. During contraction the sealing compound tends to drop below the surface of the concrete and conversely When the concrete expands the sealing compound is forced upwardly above the pavement surface.

According to the present invention there is provided a method in which many of the disadvantages described hereinbefore are avoided. According to the presently disclosed method a tubing member is inserted in the concrete while it is in the plastic state. The tubing is forced into the concrete to a point where the upper surface of the tubing is substantially flush with the upper surface of the pavement. The outwardly extending flanges at the base of the tubing prevent it from floating up during final surface finishing. The concrete is then permitted to cure completely at which time the upper surface of the tube is forced inwardly of the joint by a roller or shaping tool. The sidewalls of the tubing and upper surfaces thereof are reshaped in the form of a bellows and sealing compound is filled in between the tubing and the upper surface of the concrete. By this process the filler piece is deformed and is permitted to remain in the joint in the completed pavement.

This method has many advantages over the prior art methods described above. There is no possibility of infiltration of foreign material prior to sealing as the filler piece completely fills the formed joint and maintains a smooth even surface with the rest of the pavement. The curing of the concrete need not be disturbed by persons walking on the surface and thus a uniform curing operation is assured. Since the filler piece occupies the major portion of the joint, a minimum of sealing compound is required. The approximately square cross-section of sealed slot above the filler piece results in minimum sealer movement during summer winter cycles, resulting in maximum life of the sealed joint. The most important advantages of this method of joint formation from a commercial standpoint are that the cost of joints is not affected by hardness of aggregate, concrete cracking is controlled and a smooth riding surface is maintained, and sealed joints required minimum maintenance.

According to the present invention the member which is inserted in the concrete comprises an elongated integral member made from sheet material having a substantially planar upper surface, depending side wall portions and angular outwardly extending flanges integral with the side walls. The member is inserted in the concrete with its upper surface substantially flush with the upper surface of the concrete and with the outwardly extending flanges embedded in the concrete. When the concrete cures and contracts the embedded flanges cause the side walls to move with the concrete thereby maintaining the insert in place and preventing migration of sealer from above the insert to the subgrade.

The tubular member is embedded within the concrete with the flanges extending outwardly so as to be engaged in the concrete on each side of the joint. The upper surface of the tubular member is level with the upper surface of the concrete pavement and after the concrete is cured a roller or other suitable tool is forced into engagement with the upper surface of the tubular member so as to depress this member and to give the upper surface bellows like configuration having a central upwardly opening U. The space between the upper surface of the tubular member and the upper surface of the concrete is filled with a sealer and the joint is complete.

As the concrete contracts the joint will open up and the flanges embedded within the concrete will draw the side walls of the tubular member outwardly to maintain the side walls in close contact With the side walls of the joint. The bellows on the upper surface of the tubular member will tend to open so that the bight portion of the U will move upwardly and tend to maintain the upper surface of the sealing compound level with the upper surface of the concrete despite the fact that the joint has widened. Similarly, when the concrete expands to decrease the width of the joint the bellows will tend to close, causing the lowering of the bight portion of the U thereby maintaining the sealer level with the pavement surface despite the decrease in width of the joint.

It can be seen that a joint formed according to the present invention is completely closed at all times and there is no possibility of infiltration of foreign material either prior to or subsequent to scaling of the joint. Furthermore, since the side walls of the tubular member are maintained in close contact with the side walls of the join irrespective of expansion and contraction in the concrete by the engagement of the longitudinal flanges in the concrete, there will be no tendency for the sealing compound to migrate towards the sub grade.

A primary advantage of the present invention is to provide a method for forming joints in concrete in which foreign material is excluded and which provides a means for maintaining the upper surface of the joints substantially level with the pavement.

An object of the present invention is to provide an insert or a concrete joint which will prevent ingress of foreign material and which will maintain the sealing compound level With the concrete surface.

Another object of the present invention is to provide a tubular member which is adapted to be inserted in concrete before it is cured and which is adapted to have the upper surface thereof depressed to form a recess for sealing compound.

Other objects and many of the attendant advantages of the present invention will become apparent upon consideration of the following detailed specification in connection with the accompanying drawing wherein:

FIGS. 1 to 3 show in cross-section a concrete joint according to the present invention.

According to the present invention as shown in FIG. 1 a tubing member 9 is inserted within the concrete pavement 1%) before the concrete has hardened. This tubular member is provided with a substantially flat upper surface 11, side walls 12 and 13 which extend substantially perpendicular with respect to the upper surface 11, the side walls being inwardly bent to provide portions 14 and 15 which are adapted to be disposed in abutting relationship as shown in FIG. 1. The longitudinal edges of the member 9 is provided with angularly extending flanges 16 and 17 which extend into the concrete immediately adjacent the joint. The member may be formed from metallic sheet material and is bent into the shape shown without any connecting means being provided so that the side walls of the tubular member are free to move inwardly and outwardly.

After the concrete is cured a roller or similar tool is applied to the upper surface 11 of the tubular member so that it is deformed to provide a bellows like arrangement as shown in FIG. 2. There is a central upwardly opening U-shaped portion 18 which is depressed a substantial distance below the upper surface 19 of the concrete slab. The side wall portions 14 and 15 move outwardly with contraction of the concrete and prevent the entry of any foreign matter into the lower portion 2t) of the joint.

A sealing compound 21 is filled into the portion of the joint between the upper surface of the tubular member and the upper surface of the pavement immediately after the upper surface of the tubular member has been deformed. This prevents any foreign material from entering even the upper portion of the joint. The bellows like arrangement of the upper surface of the tubular member serves to maintain the upper surface of the sealer substantially level with the upper surface of the concrete pavement. When expansion of the concrete occurs the bight portion of the U will be lowered producing a greater volume available for sealer despite the fact that the side walls of the joint have moved slightly towards one another and when contraction occurs and the the joint is enlarged, the bight portion of the U will move upwardly.

The flanges on the tubular member insure that the side walls of the tubular member will be maintained in close contact with the side walls or" the joint and thus prevent migration of the sealer to the subgrade. It can be seen that the joint cannot receive any foreign matter due to the fact that during formation of the joint the tubular member is maintained level with the upper surface of the pavement until immediately before the sealing compound is applied.

It is also possible to use the tubular member disclosed herein without deforming the same. That is to say, the tubular member may be inserted in the concrete as shown in FIG. 1 and used in that form. The metallic member will tend to resist any effects caused by fuel propellants of rocket engines and the like when the metallic memher is used as an expansion joint in a runway or a launching pad. It is also possible to deform the member and insert an inorganic resilient material which tends to resist the corrosive effects of various fuels and the like.

Obviously many modifications and variations of the present invention are possible in light of the above teachings. What is claimed as new and desired to be secured by Letters Patent is:

l. The method of forming a joint in concrete comprising inserting a tubular member having side walls, a lower cutting edge and a flat upper surface into the surface of a slab of plastic concrete with the upper fiat surface substantially fiush with the upper slab surface, depressing and deforming the upper fiat surface of the tubular member after the concrete has hardened by forming a continuous groove therein of substantial depth to form a bellows configuration spaced from the upper surface of the concrete, and filling the space between the bellows and the surface of the concrete with a sealing material.

2. The method of forming a joint in concrete comprising inserting a tubular member having side walls, a lower cutting edge with outwardly extending flanges and a flat upper surface into the surface of a slab of plastic concrete with the upper flat surface substantially flush with the upper slab surface and with the outwardly extending flanges engaging the concrete, depressing and deforming the upper fiat surface of the tubular member after the concrete has hardened by forming a continuous groove therein of substantial depth to form a bellows configuration spaced from the upper surface of the concrete, and filling the space between the bellows and the surface of the concrete with a sealing material.

3. A method for forming a joint in concrete comprising the steps of inserting into the surface of uncured concrete a member openable along the bottom having a hollow upper end portion, abutting side wall portions extending from said hollow upper end portion and terminating in outwardly extending lower flange portions, the member being inserted into the concrete to a position wherein the upper end portion is substantially flush with the upper surface of the concrete and the outwardly extending flange portions extend into the concrete, curing the concrete with resulting concrete contraction and moving apart of the side wall portions, depressing the hollow upper end portion of the member to a level beneath the surface of the concrete, and filling the void space above the member with sealer, the engagement of the flanges in the concrete preventing migration of the sealer beneath the member.

4. A method of forming concrete joints comprising the steps of inserting into the surface of plastic concrete a tubular member having side walls converging into abutting relation, said side walls being movable with respect to each other, an openable lower edge and a substantially fiat upper wall with said upper wall substantially flush with the upper concrete surface, said lower edge separating the concrete to receive the tubular member, depressing the upper surface of the tubular member after the concrete has hardened to reduce the height of the tubular member and to form a space above the member to receive sealing material, and filling said space with a sealing material.

5. A method of forming concrete joints using a tubular member having side walls converging into abutting relation, said side walls being movable with respect to each other, an openable lower edge and a substantially fiat upper surface, the lower edge adapted to form an opening in plastic concrete to receive the tubular member, comprising the steps of inserting the tubular member into the surface of plastic concrete with the upper surface substantially flush with the upper concrete surface and the lower edge spaced from the lower surface of the concrete, depressing and deforming the upper surface of the tubular member after the concrete has hardened by forming a continuous groove therein of substantial depth to form a bellows configuration of the upper surface and portions of the side walls, portions of the side walls exerting pressure against the adjacent concrete so that the side wall portions follow the movement of the concrete, and filling the space between the bellows and the surface of the concrete with a sealing material.

6. A method of forming concrete joints by inserting a tubular member to form a weakened plane in the com crete, the tubular member having side walls having portions converging into abutting relation, said side walls being movable with respect to each other, a substantially flat upper surface, and an openable lower edge adapted to form an opening in plastic concrete to receive the tubular member and anchor means on said side walls to engage the concrete adjacent thereto, the method comprising the steps of inserting the tubular member into the upper surface of plastic concrete with the upper surface substantially flush with the upper concrete surface and with the lower edge spaced from the lower surface of the concrete, depressing and deforming the upper surface and the upper portions of the side walls of the tubular member after the concrete has hardened by forming a continuous groove therein of substantial depth to form a bellows configuration of the upper surface and side walls, the lower portions of the side Walls disposed against the concrete and adapted to move outwardly due to the engagement of the anchor means in the concrete as the concrete contracts, and filling the space between the bellows and the surface of the concrete with a sealing material.

7. A concrete joint structure comprising a member enbedded in uncured concrete, and said member having an upper surface extending substantially flush with respect to the upper surface of the concrete and adapted to be subsequently depressed after the concrete has cured to receive filler, a pair of side walls extending substantially normally with respect to said upper surface, said side walls being spaced apart and movable with respect to each other, the side Walls converging into abutting side portions, the lower edges of the side portions being provided with outwardly and upwardly extending side flange portions, said flanges embedded in the concrete in separable relationship.

8. A concrete joint structure comprising a member adapted to be embedded in the upper portion of a slab of uncured concrete, said member having a substantially flat upper surface adapted to extend substantially flush with respect to the upper surface of the concrete and adapted to be subsequently depressed after the concrete has cured to form a space thereover to receive tiller, a pair of spaced depending side walls extending substantially normally from said upper surface, said side walls converging into abutting side wall portions, outwardly and upwardly extending side flange portions on the lower edges of said side wall portions, said flange portion adapted to be anchored in the concrete slabs in separable relationship.

References Cited in the file of this patent UNITED STATES PATENTS 190,856 Henry May 15, 1877 639,961 De Man Dec. 26, 1899 1,819,304 Robertson Aug. 18, 1931 1,880,725 Bleck Oct. 4, 1932 1,903,608 Older Apr. 11, 1933 2,015,774 Weckerly et al. Oct. 1, 1935 2,066,052 Plyrn Dec. 29, 1936 2,161,333 Capouch June 6, 1939 2,162,467 Brickman et a1 June 13, 1939 2,189,437 Sandell Feb. 6, 1940 2,246,903 Spears June 24, 1941 2,316,233 Fischer Apr. 13, 1943 2,349,910 Methven May 30, 1944 OTHER REFERENCES Structural Highways, by American Concrete Expansion Joint Co., Chicago, 1934, page 13 and page 8. 

